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Speckle noise, inherent in synthetic aperture radar (SAR) images, degrades the performance of the various SAR image analysis tasks. Thus, speckle noise reduction is a critical preprocessing step for smoothing homogeneous regions while…

Computer Vision and Pattern Recognition · Computer Science 2018-01-16 Fatih Nar

Ground-based solar image restoration is a computationally expensive procedure that involves nonlinear optimization techniques. The presence of atmospheric turbulence produces perturbations in individual images that make it necessary to…

Instrumentation and Methods for Astrophysics · Physics 2023-07-26 A. Asensio Ramos , S. Esteban Pozuelo , C. Kuckein

Speckle is a multiplicative noise which affects all coherent imaging modalities including Synthetic Aperture Radar (SAR) images. The presence of speckle degrades the image quality and adversely affects the performance of SAR image…

Image and Video Processing · Electrical Eng. & Systems 2023-06-21 Malsha V. Perera , Nithin Gopalakrishnan Nair , Wele Gedara Chaminda Bandara , Vishal M. Patel

The use of ray projections to reconstruct images is a common technique in medical imaging. Dealing with incomplete data is particularly important when a patient is vulnerable to potentially damaging radiation or is unable to cope with the…

Neural and Evolutionary Computing · Computer Science 2024-06-04 Mohammad Majid al-Rifaie , Tim Blackwell

We develop a new estimation technique for recovering depth-of-field from multiple stereo images. Depth-of-field is estimated by determining the shift in image location resulting from different camera viewpoints. When this shift is not…

Applications · Statistics 2009-10-07 E. Anderes , B. Yu , V. Jovanovic , C. Moroney , M. Garay , A. Braverman , E. Clothiaux

Rotating synthetic aperture (RSA) imaging system captures images of the target scene at different rotation angles by rotating a rectangular aperture. Deblurring acquired RSA images plays a critical role in reconstructing a latent sharp…

Methodology · Statistics 2025-02-03 Dao Lin , Jian Zhang , Martin Benning

We propose a patch-based singular value shrinkage method for diffusion magnetic resonance image estimation targeted at low signal to noise ratio and accelerated acquisitions. It operates on the complex data resulting from a sensitivity…

Image and Video Processing · Electrical Eng. & Systems 2019-06-21 Lucilio Cordero-Grande , Daan Christiaens , Jana Hutter , Anthony N. Price , Joseph V. Hajnal

This study investigates some of the consequences of representing the sky by a rectangular grid of pixels on the dynamic range of images derived from radio interferometric measurements. In particular, the effects of image pixelization…

Astrophysics · Physics 2009-11-13 W. D. Cotton , Juan M. Uson

We present a versatile formulation of the convolution operation that we term a "mapped convolution." The standard convolution operation implicitly samples the pixel grid and computes a weighted sum. Our mapped convolution decouples these…

Computer Vision and Pattern Recognition · Computer Science 2019-06-27 Marc Eder , True Price , Thanh Vu , Akash Bapat , Jan-Michael Frahm

WL measurements have well-known shear estimation biases, which can be partially corrected for with the use of image simulations. We present an analysis of simulated images that mimic HST/ACS observations of high-redshift galaxy clusters,…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-26 B. Hernandez-Martin , T. Schrabback , H. Hoekstra , N. Martinet , J. Hlavacek-Larrondo , L. E. Bleem , M. D. Gladders , B. Stalder , A. A. Stark , M. Bayliss

We consider the effectiveness of foreground cleaning in the recovery of Cosmic Microwave Background (CMB) polarization sourced by gravitational waves for tensor-to-scalar ratios in the range $0<r<0.1$. Using the planned survey area,…

Scene depth estimation from stereo and monocular imagery is critical for extracting 3D information for downstream tasks such as scene understanding. Recently, learning-based methods for depth estimation have received much attention due to…

Computer Vision and Pattern Recognition · Computer Science 2021-10-12 Zhaoshuo Li , Nathan Drenkow , Hao Ding , Andy S. Ding , Alexander Lu , Francis X. Creighton , Russell H. Taylor , Mathias Unberath

Image restoration has been an extensively researched topic in numerous fields. With the advent of deep learning, a lot of the current algorithms were replaced by algorithms that are more flexible and robust. Deep networks have demonstrated…

Computer Vision and Pattern Recognition · Computer Science 2019-04-30 Rohit Jena

Radio-interferometric arrays require very precise calibration to detect the Epoch of Reionization 21-cm signal. A remarkably complete and accurate sky model is therefore needed in the patches of the sky used to perform the calibration.…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-13 Khandakar Md Asif Elahi , Samir Choudhuri , Nirupam Roy , Md Rashid , Philip Bull , Dharam Vir Lal

As recent advances in mobile camera technology have enabled the capability to capture high-resolution images, such as 4K images, the demand for an efficient deblurring model handling large motion has increased. In this paper, we discover…

Computer Vision and Pattern Recognition · Computer Science 2024-04-19 Insoo Kim , Jae Seok Choi , Geonseok Seo , Kinam Kwon , Jinwoo Shin , Hyong-Euk Lee

Upcoming ground-based cosmic microwave background experiments will provide CMB maps with high sensitivity and resolution that can be used for high fidelity lensing reconstruction. However, the sky coverage will be incomplete and the noise…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-11 Mark Mirmelstein , Julien Carron , Antony Lewis

Purpose: Many useful image quality metrics for evaluating linear image reconstruction techniques do not apply to or are difficult to interpret for non-linear image reconstruction. The vast majority of metrics employed for evaluating…

We present a new algorithm to generate a random (unclustered) version of an magnitude limited observational galaxy redshift catalogue. It takes into account both galaxy evolution and the perturbing effects of large scale structure. The key…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Shaun Cole

We use convolutional neural networks (CNNs) and recurrent neural networks (RNNs) to estimate the parameters of strong gravitational lenses from interferometric observations. We explore multiple strategies and find that the best results are…

For reconstructing large tomographic datasets fast, filtered backprojection-type or Fourier-based algorithms are still the method of choice, as they have been for decades. These robust and computationally efficient algorithms have been…

Numerical Analysis · Mathematics 2021-08-31 Poulami Somanya Ganguly , Daniël M. Pelt , Doga Gürsoy , Francesco de Carlo , K. Joost Batenburg